The invention relates to the field of compaction of a granular, loosely coherent mass, such as moist concrete mortar. Compaction of the mass results in a reduction in the air content and the production of a firm coherent product, The products concerned can be paving stones, kerbstones and a wide variety of other products made of concrete and the like.
NL-A 8004995 discloses a method for compacting concrete in which the starting material is brought into sine-wave vibration and at the same time is placed under pressure, The vibration frequency and the degree of pressure can be adjusted to the characteristics of the starting material. The installation used for this known method can be driven by electro-hydraulic means.
Although better results, that is to say lower noise production and a well-compacted end product having the desired mechanical properties, can already be obtained with this known method and installation than can be obtained with the conventional installation operating with purely electro-mechanical means, it is nevertheless found that there is still room for improvement.